Method of producing pistons



IETHOD OF PRODUCING PISTONS Filed Dec. 30, 1943 2 Shets-Sheet 1 l l I 6 INVENTOR. 9 W'F B J We M7941,

[Harri a cried Jan. 7, l d? 1 Claim.

My present invention relates to the method of producing internal combustion engine pistons having a heat radiant extending over its head end for returning heat generated by the burning fuel in the combustion spaces of the engine engaging the piston backagain into the combustion spaces, and the objects of invention are: first, to provide a method of producing internal combustion engine pistons having a heat radiant extending over its head deck; second, to provide a method of producing internal combustion engine pistons having a heat radiant at its head for returning heat of combustion from the piston back into the combustion spaces of the engine; third, to provide a methodof producing internal combustion engine pistons having a copper layered steel plate at its head deck and fastened thereto; fourth, to provide a method of producing internal combustion engine pistons having a heat radiant at the head end and exposed to combustion in the combustion spaces of the engine for returning heat of combustion to the engine spaces; fifth, to provide a method of producing an internal combustion engine piston that will cause the engine toproduce greater horse power than other typ s of internal combustion engines having the same horse power rating; sixth, to provide a method of producing internal combustion engine pistons that will not accumulate carbon at their interior or in the pressure sealing ring grooves thereby causing binding of the pressure sealing rings.

I attain these named objects and uch other objects as appear from a perusal of the follow ing description assisted by the accompanying drawings, in which-- Figure 1 is an elevation view of an internal combustion engine piston produced by my method.

Figure 2 is a cross-sectional View of the piston taken on a transverse plane extending alon line i of Figure 1.

while the head deck 4 entirely closing the opposite end of the piston casting from the annular flange 3 is being machined to provide fiat surface 5 on which to weld the radiant supporting plate 6 at the adjoinder surface 7. Numeral 8 refers to the radiant which consists of a layer of substantially pure copper rolled onto the steel supporting plate 6, or made integral with the steel plate prior to stamping or cutting the plate and radiant from the rolled sheet to circular disc form.

Numeral 9, shown in Figure 1 of the drawings, refers to the beveled edge of the heat radiant copper metal which has a greater coefficient of expansion than the ferrous metal of its supporting plate 6, or of the piston, and because of the greater coefiicient of expansion would contact the cylinder wall unduly hard and therefore consume considerable of the power of the engine by undue friction of the piston against the cylinder wall;

the thin edge of the bevel overcomes this undue friction should the heat radiant copper contact the cylinder wall as the thin edge of copper will turn down and while making a seal, adds no appreciable friction.

Adjacent the radiant supporting plate 6 is wide 1 annular flange it of slightly less diameter than Figure 3 is an enlarged cross-sectional view of the heat radiant and its supporting plate.

Figure 4 is a part sectional view of one form of apparatus for welding the radiant supporting plate with radiant layer thereon, to the head deck of the piston. 7

Throughout the four views of the drawing, similar numerals refer to similar parts and portions of the piston produced by my method and apparatus that may beemployed in carrying out my method; and referring thereto- Numeral l refers to the piston as a whole, of which 2 is the skirt portion from which extends inward, adjacent its open end, annular flange 3 for holding the piston casting by a suitable chuck,

the piston skirt 2, extending from head deck t at the interior of the piston is thickened skirt portion it into which is machined from the outer periphery of the piston, pressure sealing ring grooves 52.

Numeral it refers to the wrist pin bosses, each having bore M for accommodating the wrist pin, and numeral l5 refers to the boss at the axis of the head deck and having countersunk hole 16 for accommodating a lathe center for steadying the piston while machining away the surplus stock metal I 'l. Numeral l8 refers to the positive electrode which is employed when welding the radiant supporting plate to the head deck 4, and shown in Figure 4 in connection with one form of welding apparatus such as may be employed for welding the radiant supporting plate 8 to the head deck of the piston, which for welding, is placed on the radiant supporting plate 6 with its head deck on the radiant support 6 with its radiant copper resting on the electrode M which is cooled by cooling fluid within the chamber l9, closed by'plate 20 and supplied with cooling fluid by pipe 2! and drained by tube 22.

Bus ring 23 for delivering electric current to the positive electrode I8 consists of two semicircular members drawn tightly against the periphery of the electrode by bolts 24 and 25; the bolt 25 also serving to connect the 1 2t and thereby the electric conductor cable 2? to the bus ring. Numeral 28 refers to the negative electrode in which is cooling fluid chamber as connected to delivery tube 89 for supplying cooling fluid to the chamber and til the cooling fluid discharge tube connected to the chamber 29 at its top in screw threaded hole 82 extending axially from the chamber and is plugged by screw 33 screwed therein for connecting terminal 35 of the negative electric conductorcable 35 to the electrode. Numeral 35 refers to the conical end of the electrode 28 for forcing the contact material 3? com-, posed of either coarse particles or copper shot against the inner sides of the piston walls and thereby providing suficient electric current carrying contact capacity to prevent arcing and overheating of the piston casting, which would become sumciently great in the skirt that the skirt portion of the piston would be melted should the skirt be required to carry the major portion of the electric currentas it would be with only the stop collar 38 engaging the flat end of the skirt, which as shown, is only required to carry a small portion of the electric current. To providing a conductor for the electric current passing from the positive electrode, through the copper and its steel supporting plat and into the piston deck to which the steel supporting plate of the radiant becomes welded by reason of the resistance to the flow of electrical current raising the temperature of the steel plate and the head deck metals at their engaged surfaces sufflciently to cause a weld, when by reason of the resistance from the steel plate to the heat lessening and the breaking of the electric circuit by the operator the weld is completed. The electric current passing to the piston when making th weld between the steel plate support and the head deck, is carried to the negative electrode partly by the skirt portion of the. piston casting to the stopccllar it engaging the end of the skirt and vide adjustability of the stop collar 38, it is split at one side to permit it being drawn tightly r against the electrode by the headed screw 39.

In producing internal combustion engine pistons by my present method, and desiring to employ an apparatus similar to the apparatus shown in Figure 4 in welding the radiant supporting plate to the head deck of the piston, I provide such welding apparatus, and having provided said apparatus, I produce a ferrous metal casting of the piston including surplus metal at its portions to be machined, and when able, machine the said portions as required, and having provided the welding apparatus and the piston casting with their skirt end and head deck top machined, I

mount the welding apparatus in a powerful spot welding machine with the positive electrode l8 below and the negative electrode 28 above in sufnciently spaced apart relation to each other that the pistoncasting can be readily introduced between the separated ends of the electrodes when the negative electrode has been raised by the moveable head of the welding machine; I then moisten the flat surface of the positive electrode, and having provided a sheet of steel having a layer of copper at one of its flat sides and of less thickness than the steel from which Icut a disc which I place one of thesaid discs on the face of the positive electrode with its copper layer side in contact with the electrode, and pour into the piston casting a predetermined amount of copper metal particles, or copper shot suificlent to have its top, when leveled, at approximately the axis of the wrist pin bosses i then place the piston casting on the then upper or exposedsteel side of the disc, and having set the stop collar it at a position on the electrode that will permit the electrode being introduced with its round apex to within required distance from the clamped to the negative electrode, and partly by the copper metal particles or copper shot 37 engaging the head deck, the side wall of the piston casting and the said negative electrode from which the electric current is conveyed by cable 25.

Having described my present method of producing internal combustion pistons, I claim:

The herein described method of producing pis tons, which method comprises; providing a hollow piston casting of ferrous metal and having aportion closing one of its ends, machining the end closing portion at its side exterior of the piston casting, providing an electrode having an electricity transfer surface conforming substantially to the form of the machined side of the said end closing portion, providing a ferrous metal plate l having .at one of its flatter sides a layer of copper and of suficient edges to edges size to extend over the end closing portion of the piston casting, mounting the said plate on the said electrade with its copper layer in engagement with the electricity transfer surface of the aforesaid electrode, mounting the piston castingon the said plat with the machined surface of the end closing portion in engagement with the said plate at its ferrous metal side, placing a quantity of metal particles having a high heat conduction value in the piston casting and against the end closing portion, providing another electrode of 

